污水厂尾水反硝化滤池生物/化学协同脱氮除磷研究

Cooperative Processes of Denitrification Filter and Chemical for Nitrogen and Phosphorus Removal in Tail Water from Wastewater Treatment Plant

在反硝化滤池生物脱氮系统构建成功的基础上,投加除磷药剂建立生物/化学协同处理系统,重点研究了除磷药剂种类、投加量对该工艺处理污水厂尾水效能及微生物种群的影响。结果表明,除磷药剂种类(Fe Cl_3、Al Cl_3、氢氧化钙)及其投加量对系统脱氮效果的影响不显著,但对除磷效果影响显著,投加Al Cl_3的除磷效果较优;在温度为25~35℃、水力负荷为3 m^3/(m^2·h)、补充碳源后的COD/TN为6、Al Cl_3投加量为3.0 mg/L时,系统出水NH_4^+-N、TN、PO_4^(3-)-P浓度分别为1.72、1.73、0.19 mg/L,去除率分别为57.10%、91.69%、81.68%,可稳定达到地表水环境Ⅴ类水体标准。PCR-DGGE和16S rRNA高通量测序结果表明,反硝化滤池生物/化学协同处理系统中脱氮功能菌属主要有Hydrogenophaga、Thauera、Dechloromonas、Zoogloea,其相对丰度分别为24.07%、12.26%、8.50%、0.44%;投加除磷药剂的协同处理系统与生物脱氮系统的微生物种群相似性为49.9%,生物多样性降低。

Cooperative nitrogen and phosphorus removal system using biological and chemical processes was applied to treat tail water from a wastewater treatment plant. The impact of agent type and dosage on the removal efficiency and microbial community was investigated. On the basis of biological ni- trogen removal system, phosphorus removal agent was added to start up biological - chemical synergistic system in denitrification filter. Phosphorus removal agent such as FeC13, A1C13, Ca（OH）2 and its dosage were not significant for the denitrification effect but had significant effect on phosphorus removal in the co- processing system, and A1C13 was better than other two agents. At the temperature of 25 - 35 ~C, hydrau- lic loading of 3 m3/（ m2 ~ h）, supplying carbon source as COD/TN of 6 and the A1C13 dosage of 3.0 mg/ L, the average effluent concentrations of NH4＋ - N, TN and PO^- - P were 1.72 rag/L, 1.73 mg/L and 0.19 mg/L, respectively, corresponding to the removal rates of 57.10%, 91.69% and 81.68%, re- spectively. The effluent quality could reach class V of Environmental Quality Standard for Surface Water.Based on the results of PCR-DGGE and 16S rRNA, the denitrifying bacterial strains in the biological - chemical synergistic system were mainly Hydrogenophaga, Thauera, Dechloromonas and Zoogloea, corre- sponding to the percentage of 24.07%, 12.26%, 8.50% and 0.44%, respectively. Moreover, the mi- crobial community similarity between the cooperative treatment system and the biological nitrogen removal system without agent was 49.9%, and the biological diversity decreased.